Meeting invitations shown as normal message

eM Client does recognize invitations correctly and offers reply-options (accept meeting etc…)
but in the list of messages (eg. Inbox) meeting invitations do not show a special icon.

I do understand that an invitation is technically also just an eMail-message, but a specific icon will help to make them stand out in a list of messages.
Perhaps a calendar-icon in front of the senders name?

example: